The pharmaceutical drug discovery and development involves generation of many drug substances and formulations. However, most of them might not be the suitable candidate for further commercialization. Thus, prior to their commercialization, a new chemical entity should demonstrate its intended efficacy and safety both clinically and pre-clinically. In addition to offering a unique selling point, the effective treatment should even accomplish the unmet medical requirements. Objectives of TOX studies – The key objectives of performing IND enabled Tox studies can be summed up as follows – Any pharmaceutical product under development should go through a thorough screening of safety and efficacy both in human and animal models. FDA recommend toxicology studies in drug development to be performed in alignment with the international standards for harmonization of non-clinical trials. These are in fact, the pre-requisites for laying the foundation of the clinical trials to be conducted with the same scope and duration. To seek marketing approval, it is important to seek non-clinical characterization. What are tk studies? Toxicological studies are imperative for the development process of pharmaceutical product and their approval. Both pre and non-clinical toxicology studies requires a minimum of two species under USFDA regulations. Such studies need to be performed as per the requirements under 21 CFR and GLP for non-clinical laboratory testing. A combination of both these guidances compliance ensures that the test subjects have been handled with utmost care and reliability of the scientific data obtained. Most of the new pharmaceutical entities fail to qualify these IND enabling toxicology studies. In turn, they demonstrate toxicity or adverse events when they are dosed at a level higher than their usual recommendation. Both the pre-clinical and toxicokinetic studies helps in the determination whether the drug is safe to be initially tested in the humans. This testing helps the clinical researcher to define the fine line between the therapy and overdosing. Exploratory IND studies – Exploratory IND enabling studies are also referred to as micro-dose studies or clinical screening studies. USFDA defines such studies as Phase 1 clinical trials wherein you have a limited human exposure and little to no therapeutic or diagnostic intention. Such studies assists the organizations in evaluating feasibility of further drug development process prior to its dose escalation, tolerance, and safety studies. As these studies involve dose administration either at sub-pharmacologic dose levels of a pharmaceutical drug product, they pose a lower potential risk to humans. The pharmaceutical doses are sub-efficacious; yet these studies provide following valuable information – Evaluation of whether a drug’s mechanism of action under evaluation for the in vivo animal testing procedure exhibits the same results when it is administered in the same dose levels. This provides critical details regarding the clinical pharmacokinetic characterization of the pharmaceutical product under consideration. Out the usual candidature list, it becomes imperative for selecting the most promising pharmaceutical drug candidate for the next phase of clinical evaluation. This is done in alignment with the pharmacokinetic or pharmacodynamic drug characterization requirements. Evaluate and explore the bio-distribution or bioequivalence clinical trials of the pharmaceutical drug candidate under analysis with the essential techniques.